The present invention relates to a device for entraining a shaft door by means of a lift car door according to the preamble of claim 1. A device of this type is also called a coupling gearing.
Lift doors usually have a door provided on the lift car as well as shaft doors provided at each floor. When the lift car approaches a floor, it is necessary for both the lift car door and the corresponding shaft door (then positioned behind the lift car door) to be opened and closed to allow passengers to get into and out of the lift and to allow the lift car to continue on its way.
A lift car door usually has a drive by which it can be opened and closed. To avoid corresponding drives for every shaft door, the lift car door is configured with a catch or entrainment mechanism which, when the lift car arrives at a floor, engages in a corresponding counter-catch of the shaft door and also opens and closes the shaft door. In this respect, expanding hook bolt mechanisms are usually used, as described, for example, in EP 0 744 373 B1.
A disadvantage of the mechanism described in that document is that when the lift car moves, the catch and counter-catch project into the threshold spacing, i.e. into the spacing between shaft door threshold and lift car door threshold, which can result in rattling and wind noises when the lift car moves relatively fast, because for example when passing through a floor (without stopping), the catch and counter-catch are moved very closely past one another. In other words, the effective spacing between lift car door and shaft door is significantly smaller than the threshold spacing.
In particular in the case of a so-called high-power lift car door, it is essential to prevent rattling and wind noise at very fast travelling speeds. Furthermore, lift doors of this type are to open and close as fast as possible.